Directional Survey Technology of Shield-driven Tunneling Technique for Yangtze River Pipeline Crossing of West-to-East Gas Transmission Pipeline Project

In the paper, the shield-driven tunneling technique used in Honghuatao pipeline crossing in Yangtze River for West-to-East Gas Transmission Pipeline Project is introduced. In the light of this technique's characteristics,the analysis on the survey pass-through error is made. According to the comparison results of different survey programs, the tying triangle directional survey program is presented to directionally survey the vertical shaft and is successfully applied to this pipeline project.